1. Before 1/3/2023 the Democrats panic and push for Biden to step down. Harris is sworn in and (known Democrat) will be VP insuring they have some game plan to keep the WH.
2. After 1/3/2023 (new Congress) Harris, because at this pace the odds are Biden will not serve the entire time he has left.
3. Trump will be back in 2024. I see Desantis following Trump's lead as VP and then as President 2028-2036.